The police and ambulance arrive quickly

This isn't Oliver's first crime

Oliver has a history of traffic offences; speeding, running red lights, refusing to hand over his keys, careless driving, and dangerous driving. In the past, he has been sentenced to community work and disqualified from driving for six months. He's only had his licence for three years, but he's already been disqualified for 12 months during that time.

At the hospital, the police officer decides not to question Oliver, but he arranges for Oliver to give a blood sample to see if there is any alcohol is in his system.

Gathering evidence

Back at the scene of the crash, the police's Serious Crash Unit (SCU) arrives quickly. The road is closed and the SCU unit begins to gather evidence and tries to piece together what happened. They talk to the driver of the van, who received only minor injuries but was badly shaken. Detectives from the Criminal Investigation Bureau (CIB) visit the scene briefly, but they aren't needed.

Oliver is arrested

Late the following day, Oliver goes home from hospital.

The Officer in Charge (OIC) has already talked briefly with the police legal section and the Crown Solicitor's office about what charges should be laid – that is, what crimes Oliver will be charged with. The Crown Solicitor's office decides whether cases brought by the police will proceed to the criminal court. Its lawyers represent the police in serious cases.

The OIC of the case visits Oliver at home, arrests him and charges him with manslaughter (killing without intent), and reckless driving causing injury. Police now call Oliver the "alleged offender".

Innocent until proven guilty – Oliver's rights

Oliver is seen as innocent until proven guilty.

Under the Bill of Rights Act 1990, if you are charged with a crime, you have the right to be presumed innocent until proven guilty in a court of law. "The presumption of innocence" is a basic right under New Zealand's criminal justice system.

The OIC informs Oliver of his rights and responsibilities under the Bill of Rights, including:

his right to not say anything (make a statement) – although if he decides to, anything he says may be used as evidence against him

his right to talk with a lawyer as soon as possible and in private. If he doesn't have a lawyer, he can ask to see the list of lawyers he can consult for free under the Police Detention Legal Assistance (PDLA) scheme. Oliver must be able to talk freely with his lawyer, without the police listening to the conversation.

Deciding the criminal charges

While this is happening, the police are gathering more evidence for the case.

At the end of the interview process, they will decide whether there is enough evidence to charge Oliver.

In this case, there is. Oliver is formally charged with specific offences - two charges of manslaughter and one charge of reckless driving causing injury. He is again cautioned - reminded - that anything he says will be taken down in writing and may later be used as evidence against him.

They will make contact with and offer to help the victims and their families deal with the emotional and physical impacts of the crash.

A police investigation team continues to gather evidence. They check the vehicles for exhibits (pieces of evidence) and talk to the victims and witnesses, and to Oliver's friends and family. All of the information they gather goes into the case file.

What else could happen to an alleged offender?

There are 4 different categories of offences and the way in which offenders will be processed depends on the category of offence that they are charged with. These categories are determined by the maximum sentence which can be imposed. The category of the offence also determines what type of trial will occur and where the trial will be held:

A category 1 offence is an offence that is punishable by a fine only, for example, careless driving. These offences will be heard in the District Court by a judicial officer (rather than a jury).

A category 2 offence is an offence punishable by a maximum term of imprisonment of less than two years (or not punishable by a term of imprisonment but with a community-based sentence as a maximum penalty). These offences may be heard in either the District Court or High Court by a judicial officer (rather than a jury).

A category 3 offence is an offence punishable by imprisonment for life or a maximum term of imprisonment of two or more years unless listed in Schedule 1 to the Criminal Procedure Act 2011. These offences may be heard in either the District Court or High Court by a judge alone or a judge and a jury.

A category 4 offence is an offence listed in Schedule 1 to the Criminal Procedure Act 2011. These are the most serious offences, for example, murder or manslaughter.

Oliver is charged with manslaughter, a category 4 offence. Although these things didn't happen to him when he was processed, other category 4 offenders might:

have their clothes taken for evidence to link them to the crime. They would be given a pair of police-issue white overalls to wear.

have a DNA sample taken.

be checked to see whether they have been taking drugs or drinking alcohol.

be checked for signs of depression or being suicidal so they can be watched and managed properly. If they were on drugs or had mental health problems, a Critical Assessment Team (CAT) from the local District Health Board may be called in.